Different types of glass containers coated with a synthetic material using different coating methods and different synthetic materials are well-known from numerous publications.
In this manner a solvent free polyurethane is applied in a specific blend of predetermined thickness and/or tension firmness and flexibility to a glass container in patent number DE 23 12 694 C3
DE 27 09 451 C2 describes a coated glass bottle, its upper exterior surface being coated with a layer of a thermally hardening material which is developed from a powder that contains a mixture of a locked organic polyisocyanate and a hydrolyzed ethyl vinylesthercopolymer and/or a carboxyl modified version of the hydrolyzed copolymer.
DE-AS 26 09 931 describes a method by which a mixture of an elastomer organic polymer and an organic peroxide compound is applied to the surface of a glass container and the way in which this coating mixture is applied in situ using an energy charge in such a way that the polymer is cross linked.
The process by which the coating and/or encasings of a glass bottle is applied using high pressure is known from DE-AS 23 37 331 and DE-OS 23 30 804.
This protective synthetic coating ensures that shards of broken glass are held together should the coated glass container break. In this manner, the synthetic coating functions to protect against shattering and splintering.
The above described glass container technique pertains to beer bottles, cosmetics containers and other similar containers.
However, the present invention relates to a special form of container namely pressurized containers, which are filled under pressure with, in particular, medically active substances and a propellant and which are closed using a dispensary organ, particularly a dosage valve, over the opening. When using a delivery head, which works with the dispensary organ in such a manner that when both parts are pressed together, the dispensary organ is activated and a predetermined dosage of the medically active substance is released as aerosol through a spray nozzle, these products are used as an applicator for medical uses, in particular for use by asthmatics and other people suffering from bronchia.
Such applicators generally consist of pressurized containers made from metallic materials. Such containers are protected against shattering and splintering by use of a material not prone to shattering (durability and strength).
The disadvantage of these pressurized containers, however, is that the non-transparent material does not allow visual determination of the amount of substance remaining to be administered. This is particularly a disadvantage because inhalant preparations often are utilized in emergency treatment (for example asthma medication). When visual determination of the contents of the container is not possible, the container could be empty when emergency medication would be necessary.
Pressurized containers in the form of a glass bottle are also well-known. The content volume of the bottles can vary between 5-50 ml. The upper end of the bottle is fitted with the outflow opening. Generally, this opening is closed by the pressing on and/or bending of the dispensary organ on the pressurized container, for example a dosage valve with a usually cylindrical upward reaching cannula, often used with an elastic seal between the head and the dosage valve.
The well known pressurized glass container is coated with a transparent synthetic material which is sprayed on or into which it is dipped except for the rim on which the dosage valve is attached. This coating consists of a very flexible soft synthetic material, for example polyvinyl chloride. The strechable effect is important since the pressure build-up caused by the shattering of the container affects the soft synthetic material. should the soft synthetic material not be able to give by changing volume when exposed to pressure, a sudden soft synthetic material destruction caused by dissolving or stress corrosion is to be expected.
This well-known pressurized container has the advantage in that the use of a transparent material (glass) and a transparent synthetic coating allows easy determination of the amount of substance remaining in the container.
The disadvantage of the pressurized container is that the transparent pressurized glass container is not safe in case of explosion, caused for example from improper handling, despite being coated with a synthetic material, since the coating especially in the area of the dosage valve cannot prevent pieces of the glass container from being shot out into the surrounding area because the coating will billow out in a balloon like fashion.
Also well-known are applicators (GB 2 109 333 A) which in the framework of the assembly of the applicator, show the glass pressurized container fitted with a closely fitting shell portion, a protective shield. This concept has the disadvantage that the production and assembly expenditure is higher. The same applies to the well-known applicator GB 2 214 891, which consists of a flexible synthetic pressurized container housed in a solid synthetic shell portion.
However, this invention depends on the unusual concept that in the framework of the production of the final pressurized container, the synthetic shattering and splintering protection shield is applied directly onto the glass pressurized container by covering it with an extruded thermoplastic using injection molding equipment
Such a conception is well-known from FR 2 631 581 B1. This publication describes the initially mentioned glass bottle with a narrowed neck, which can be filled under pressure with a substance that can be sprayed as an aerosol and with a propellant. The opening is closed with a dispensary organ and the bottle is sprayed with a synthetic covering.
In the best known case, the glass pressurized container consists of a bottle with a cylindrical neck and the injection mold is fashioned in such a way that both the neck and the bottle opening are sprayed with the synthetic material. However, the safe placement of the dispensary organ of the dosage valve is not without problems when the neck of the bottle is designed in this fashion. The synthetic coating covers the entire glass bottle. If the glass bottle shatters, the shatter and splinter protection properties may be lost because the coating partially billows out and bursts. No mention is made of the kind of synthetic material used in the above mentioned publication, which suggests that it is not considered critical to the function of the invention.